str1 = "hello world"
str2 = 'hello world'
str3 = '''hello 
world'''
# \转译符
print('hel\'lo world')

print("123---{0}".format(4))
str1 = "cxk"
print(f"sb--->{str1}")

# 控制台模拟下载进度‘
for i in range(0, 101, 2):
    print("================开始下载==================".center(58))
    if i == 100:
        print("下载完成")
    else:
        tem = "*" * (i // 2) + "." * (50 - (i // 2))
        print(f"{i}%", '[', tem, "]")
